Emulsion high-pressure homogenisers

Reducing the emulsion droplet size by using high-pressure homogenisation. The smaller droplets are less deformable and coalescence is prevented. In addition, the accumulation of suspension particles at the O/W interface is prevented. 

Ease of manufacture and scale up The spontaneity of formation of micro emulsions makes their manufacturing and scale up very easy as compared to other colloidal carriers such as emulsions or liposomes which require specialised instruments such as high pressure homogenisers for their manufacturing. 

For emulsions rotor-stator mixer, high pressure homogeniser, ointment mill. 

Two methods may be applied for the preparation of nano-emulsions (covering the droplet radius size range 50-200 nm). Use of high-pressure homogenisers (aided by appropriate choice of surfactants and cosurfactants) or application of the phase inversion temperature (PIT) concept. 

In all cases, there is an increase in nano-emulsion radius with increasing f (0/S). However, when using the high-pressure homogeniser, the droplet size can be maintained to below 100 nm at high J (0/S). With the PIT method, there is a rapid increase in r with increase in i (0/S) when the latter exceeds 7. 

As expected, nano-emulsions prepared using high-pressure homogenisation showed a lower Ostwald ripening rate than systems prepared using the PIT method. This is illustrated in Figure 9.17, which shows plots of versus time for the two systems. 

Fat emulsions must have a small particle size (200-500 nm), which requires the use of high-pressure homogenisers. It is essential to store the emulsion at various temperatures and investigate any increase in fatty acid composition that causes lipoprotein lipase reactions. Also, an increase in droplet size increased the toxicity of the emulsion. Addition of drugs and nutrients to fat emulsions can also cause instability and/or cracking of the emulsion. Following the administration of fat emulsions to the body, it will be distributed rapidly throughout the circulation and then cleared. 

In all experiments, emulsions were prepared using a high pressure homogeniser (Panda 2K or Panda 2000, GEA Niro Soavi, Liibeck, Germany). Microcapsules were prepared by spray-drying on a pilot plant spray dryer (Mobile Minor, Niro A/S, Copenhagen, Denmark). Specific conditions are provided in the figures and tables. 

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